coahran



J. M. COAHRAN led May 26, 1925 Aug. 14, 1928.

METHOD AND MEANS FOR PREVENTING LOSSES IN CLOSED CIRCUIT TREATING APPARATUS Patented Aug. 14, 1928.

UNITED s'rArEs PATENT OFFICE.

JESSE M. COAHRAN, 0F COLEGROVE, PENNSYLVANIA, ASSIGNO TO OLEAN SALES CORPORATION, OF CLEAN, NEW YORK, A CORPORATIONl OF DELAWARE.

METHODVAND EEANs Fon PREVENTING LosSEs IN CLOSED-CIRCUIT TREATING i v APPARATUS. Y

Application led May 26, 1925. Serial No. 33,032.

In industrial processes it is sometimes desired to treat materia-l with a fluid, as for extracting "certain constituents or substances therefrom, .then to separate said constitu-` ents from the fluid and return the fluid to contact with other untreated material. The same fluid is thus used over V.andy over in a closed circuit or cyclic treating system.

The objectvof the `present invention is to prevent leakage losses of this fluid. Not only is itdesirable to prevent such leakage because of' the expense of replacing the amount of fluid "so 10st,'bu`t in many instances the fluid usedl is of a` volatile and of' a dangerous nature when present in the atmosphere.` i'

According to' this invention, therefore, provision i'smade for maintaining that ortion of the apparatus infwhich the uid circulates at substantially atmospheric pressure so that the tendency for loss of fluid through leakage from the 'oints therein 1s reduced, this being accomplished by providing a vent therefrom to the atmosphere. As, however, such a vent if usedalone would permit the free' escape of fluid or vapors, means is interposed adjacent tothe vent outlet for subjecting any fluid or vapors passing toward this outlet to contact with some of the raw material which is to be treated by the fluid. The treating "fluid and vapors passing to thevent are thus absorbed by thisl material, permitting only inert fluids which may have entered the apparatus accidentally, as with the raw 'material to be treated, to escape.` This raw material with its absorbed fluid is then passed with the other raw material tovbe treated into that ortion` of the apparatus where the main ody of the fluid is brought into `contact therewith. Fluids which would otherwise berwasted are thus reclaimed and thepressure of the fluid in the system is maintained so near atmosphericthat theV leakage loss otherwise A.inevitably occurring is materiall reduced. Also vapor temperatures which must loe` very accurately maintained and which are greatly affected by pressure are under `much better control and `sulojectrto much less variation on account of the submore acid liquor.

stantially constant,

h l substantially atmosp eric ressure maintained.

As il ustrative` of a process and an appa- Referring to this drawing, 1 indicates Va receptacle in which the pyroligneous acid liquor is stored and which serves as a source of the acid liquor to be treated. Acid from this tank is passed through a valved pipe line 2 to the upper portion of an extractor column 3,.the pipe as shown having a downwardly looped portion fi therein to serve as a trap. Aty is shown anether storage tank from which the ether passes through the pipe line 6 to the pumpf? from which it is pumped into the lower portion of the extractor co1- umn 3 through the pipe 8. The ether passes upwardly through the extractor column 3,

coming in `intimate contactwith the acid liquor passing downwardly through this column and extracting acid therefrom. i The acid laden ether passes out from the upper portion of` the extractor through the pipe 9 above the entrance of the acid liquor and is trapped through this pipe 9 to the ether fractionating column 10 having a steam heated still 11. lhe ether vapors in this column freed from acid pass out into the other condenser l2 and are returned through the trappcdfline `13 to the storage or supply tank 45; The acid accumulates 4in the lower` portion ofthe still 11 at the bottom of the fractionating column. v y

The waste liquor passes from the fractionating column 3 through the` pipe 14 and contains some ether and thisis conducted to a columnl into the lower portion of which steam is introduced as through the pipek 16 by which theether isv driven off through the pipe 17 and passes into the vapor line from the fractionating column 10 and from thence to the ether condenserl 12. The waste liquor free from ether passes out through the pipe 18 from the lowei` end of the coluinnl.'

VAs ether is quite volatile, and as some noncondensable gases are inevitably continually introduced Ainto the system with the liquor and ether, should no vent to the atmosphere be provided, the pressure in the cyclic system in which the ether is used would rise considerably above atmospheric, whereupon the ether vapors would ,quickly find any leaks in the system and escape to the atmosphere, and traps ,ordinarily provided on the ether system would be blown to atmosphere. In order to avoid the raising of such 'pressure materially above atmospheric the pipe 13 is shown as connected to a pipe 20 and the ,ether ysupply or storage tank 5 is connected t0 the pipe 21 and the extractor to a pipe 19, all of these pipes 19, 2O and 21 communieating with a pipe 2N2 which leads to the lower portion 0f a scrubber 23, the upper portion of the scrubber being open to the atmosphere through the vent pipe 2 4. Should pressure occur in the ether system above atmospheric this would immediately be relieved byV How Vof ether or vapors toward the vent, but it is desirable that only the inert gases such as air and the like which have passedinto the system incidentally, as with the acid'liquor from the source of supply 1, be permitted to escape. The scrubber 23,

therefore, provides means by which anyv ether or vapors passing toward the vent may be intercepted and absorbed, and for this purpose acid liquoi` is supplied to the upper portion of the scrubber through the pipe 25. This acid liquor passes down through the scrubber and any vapors or fluids from the ether system as they pass toward the vent 24: are brought into intimate contact with this liquor. This Vscrubber may be packedvwith any suitable surface providing material so that intimate contact between the downwardly trickling acid liquor and the up# wardly liowing vapors entering 'from the pipe 22 is effected. The acid liquor in the scrubber absorbs any ether passing into the scrubber and the acid liquor' containing such absorbed ether is passed out of thescrubber through the pipe 26 into .the pipe 4 and is' thus conducted to the extractor column 3 with the acid liquor flowing direct from the source 1 thereto. By this means the pressure in the ether system is reduced to substantially atmospheric, the scrubber itself interposing only a small resistance to free flow of vapors from the ether system, and at the saine timeany ether which would otherwise Vescape therefrom is caught and returned to .the system for later recovery and reuse as solvent for the acid.

While this invention vhas been described 'terial to be treated by said fluid.

2.y The method of preventing leakage from f the system in which a solvent is employed to dissolve substances vfrom material treated, which substances are recoveredtherefrom and the solvent returned rto treat more ma# terial, which comprises venting such system to the atmosphere, absorbing solvent tendingV to escape through the vent by fresh mate-v i rial, and then subjecting said fresh material with absorbed vsolvent `to the action of the main body of solvent.

3. The process which comprises passing acetic acid in continuous countercurrent flow contact whereby the ether dissolves and carries acid away with it, subjecting the acid laden ether to continuousdistillation to rer' move the ether from ythe acid, condensing theVV ether and returning it to the countercurrent flow, Vand maintaining the pressure of the ether at substantially atmospheric. v

4T. The process which comprises passing acetic acid and ether in continuous countercurrent flow contactfwhereby the ether dissolves and carriesacid away with it, subloir jecting the acid ladenV ether to continuousV distillation to remove the ether from the acid, condensing the ether and returning it to the countercurrent flow, recovering from the treated Iacid liquor ether contained y 'therein' and returning it to the system and maintaining the pressure of the ether at substantially atmospheric..

5. The process which comprises passing acetic acid and yether in continuous counterlll) current flow ,contact whereby the ether dis.- y

solves and carries acid away with it, subjecting the acid laden ether to continuous dis.-

.tillation to remove the ether from the acid,

condensing the ether and lreturning it to the countercurrent How, and absorbing ether tending to escape to atmosphere in fresh acid containing liquori*r 6, The process which comprises passing acetic acid and .ether in continuous counter'- current flow contact wherebythe ether dissolves and carries acid away with it, subjecting the yacid laden ether to continuous distillation'to remove the ether from the acid, condensing the ether land returningV it to the countercurrent flow, absorbing ether tending to escape to atmosphere in fresh acid containin liquor, and passing such liquor and et er to such countercurrent flow. Y.

7. An apparatus comprising a source of material to be treated, a fluid supply, means for subjecting material from said source to the action of-fluid from said supply, means for drawing off said luid togetherwith substances dissolved thereby from said sub.- jecting 1neans,.me`ans for drawingoiif spent material from said subjecting means, means for recovering the dissolved substances and returning the fluid from which such substances are recovered to said supply, means for venting said supply to the atmosphere, means interposed. between said venting means and supply for treating fluid passing toward said venting means With material from said source to absorb such fluid, and

means for passing such material and absorbed fluid to said subjecting means;

8. An apparatus comprising an extractor, means for delivering material having substances to be extracted to said extractor, means for delivering a solvent for such substances to said extractor, means for removing spent material from said extractor, means for removing substance containing solvent from said extractor', means for separating the substance from the solvent, means for returning the solvent to 'said extractor, a vent for maintaining said solvent at substantially atmospheric pressure, means to absorb with untreated material `solvent tending to escape throughsaid vent, and means for conducting said untreated material and absorbed solvent to said extractor.

9. An apparatus comprising anextractor,

means for delivering material having substances to be extracted to said extractor, means for delivering a solvent for such substances to` said extractor, means for removing spent material from said extractor, means for recovering solvent from said spent material and returning to said extractor, Ineans for removing substance containing solvent from said extractor, means for separating the substance from the solvent, means for returning the solvent to said extractor, a vent for maintaining said solvent at substantially atmospheric pressure, means to absorb with untreated material solvent tending to escape through said vent, and means for conducting said untreated material and absorbed solvent to said extractor.

l0. An apparatus comprising an extractor, means fordelivering acid laden liquor to said extractor, means for delivering a volatile solvent for such acid to said extractor,

means for removing the acid laden solvent 'from said extractor, a still for driving oif solvent Yfrom said acid, a condenser for receiving and condensing the solvent from said still, means for returning such condensed solvent to said extractor, a scrubber' through Which acid laden liquor passes on its way to said extractor, said scrubber having a vent to atmosphere, and a connection for said solvent to said scrubber from between said condenser and extractor and from said extractor, such that solvent tending to escape through said vent is absorbed by liquor passing through said scrubber.

In testimony whereof I have aixed my signature.

JESSE M. COAHRAN. 

